40 research outputs found
Heptamethine cyanine dyes in the design of photoactive carbon nanomaterials
Near-infrared (NIR) absorbing nanomaterials, built from anionic heptamethine cyanine dyes and single walled carbon nanotubes (SWCNTs) or few layer graphene (FLG), are presented. The covalent linkage, by using 1,3-dipolar cycloaddition reactions, results in nanoconjugates that synchronize the properties of both materials as demonstrated by the thoughtful characterization study carried out by transmission electron microscopy (TEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). UV-Vis-NIR and Raman spectroscopies further confirmed the unique electronic structure of the novel photoactive nanomaterials
Competitive Retro-Cycloaddition Reaction in Fullerene Dimers Connected through Pyrrolidino-pyrazolino Rings
International audienc
Switching the Stereoselectivity: (Fullero)Pyrrolidines âa la Carteâ
Stereodivergent syntheses of <i>cis</i>/<i>trans</i> pyrrolidinoÂ[3,4:1,2]Âfullerenes and <i>endo</i>/<i>exo</i> pyrrolidines are reported with high enantioselectivity
levels. Fullerenes are revealed as a useful benchmark to develop suitable
catalysts to control the stereochemical outcome and to shed light
on the mechanism involved in the related 1,3-dipolar cycloaddition
Supramolecular Electronic Interactions in PorphyrinâSWCNT Hybrids through AmidiniumâCarboxylate Connectivity
New supramolecular (metal)Âporphyrin/SWCNT
hybrids have been synthesized
through a combination of hydrogen bond and electrostatic interactions.
Our experimental findings reveal through different techniques (XPS,
TGA, UVâvis, Raman, and TEM) an efficient n-doping of the SWCNT
from the electron donor (metal)Âporphyrin through the efficient and
strong amidiniumâcarboxylate connectivity
ExTTF-Based Dyes Absorbing over the Whole Visible Spectrum
International audienceNew pushâpull dyes featuring Ï-extended tetrathiafulvalene (exTTF) as the donor group and tricyanofuran (TCF) as the acceptor group were synthesized and characterized. Their broad absorption covers the entire visible spectral range and enters the near-infrared region. Electrochemistry and theoretical calculations provided an understanding of these singular electronic properties. The new dyes are appealing candidates as light harvesters in photovoltaic devices
Maleimide and Cyclooctyne-Based Hexakis-Adducts of Fullerene: Multivalent Scaffolds for Copper-Free Click Chemistry on Fullerenes
The
synthesis of multivalent systems based on hexakis-adducts of
[60]Âfullerene employing a biocompatible copper-free click chemistry
strategy has been accomplished. A symmetric hexakis-adduct of fullerene
bearing 12 maleimide units (<b>3</b>) is reported, and it has
been employed to carry out the thiol-maleimide Michael addition. To
achieve orthogonal click addition, an asymmetric derivative bearing
one maleimide and 10 cyclooctynes has been synthesized. The sequential
and one-pot transformations of the two clickable groups have been
explored, finding the best results in the case of the one-pot experiment.
This route has been used to obtain a biocompatible hexakis-adduct
appended with two different biomolecules, carbohydrates, and amino
acids
Nanorods versus Nanovesicles from Amphiphilic Dendrofullerenes
Three new amphiphilic dendrofullerenes endowed with 4, 8, and 16 carboxylic groups have been efficiently prepared by using a click chemistry methodology. These amphiphilic fullerene derivatives aggregate forming micelles, nanorods, or hollow vesicles depending on the concentration and on the solid substrate
Coordinating Electron Transport Chains to an Electron Donor
Two electron transport
chains (<b>2</b> and <b>3</b>) featuring two fullerenes
with different electron acceptor strengths
have been synthesized, characterized, and coordinated to a light harvesting/electron
donating zinc porphyrin. Electrochemical assays corroborate the redox
gradients along the designed electron transport chains, and complementary
absorption and fluorescence titrations prove the assembly of ZnP-<b>2</b> and ZnP-<b>3</b> hybrids